Conventionally, there is known an internal combustion engine that executes compression ignition of fuel in a combustion chamber. For example, Japanese Unexamined Patent Application, Publication No. 2009-287549 discloses an internal combustion engine of this kind that emits electromagnetic waves to a combustion chamber to generate electromagnetic wave plasma.
More particularly, in the internal combustion engine disclosed in Japanese Unexamined Patent Application, Publication No. 2009-287549, when a piston is placed in the vicinity of the top dead center, an injector injects fuel, and the injected fuel is ignited. In the combustion chamber, aflame is formed centered on the injector. Then, a microwave pulse is supplied in a region in the vicinity of the flame, electrons in the flame are energized and accelerated while receiving the energy therefrom, and the accelerated electrons collide with ambient molecules. The collision molecules are ionized to form plasma. Also, free electrons in the plasma are energized and accelerated, and ambient molecules collide with the electrons and become plasma. In this internal combustion engine, an avalanche-like generation of plasma occurs, and comparatively large plasma is generated.
Furthermore, as a fuel injection device that injects fuel in a compression ignition internal combustion engine, for example, Japanese Unexamined Patent Application, Publication No. 2010-255484 discloses a fuel injection device that executes a multiple injection. The fuel injection device executes a plurality of fuel injections including at least a pilot injection and a main injection during one combustion cycle.